The present invention relates to a rotating type scroll compressor for use with a freezing, air-conditioning, and hot water supplying fluid apparatus, in particular, to improvements of supporting a scroll member of a rotating type scroll compressor and sealing in a radial direction thereof.
As a first related art reference shown in FIG. 8A is a vertical sectional view of an embodiment of a scroll compressor as disclosed in Japanese Patent Laid-Open Publication No. 4-8888. FIG. 8B is a sectional view taken along line A--A of FIG. 8A. Next, the components of the embodiment will be described.
In FIGS. 8A and 8B, reference numeral 1 is a closed shell. An electric drive member 2 is housed at a lower position of the shell. A scroll compressing member 3 is housed at an upper portion of the shell. The electric drive member 2 is composed of a stator 4 and a rotor 5 disposed therein. Between the stator 4 and the rotor 5, an air gap 6 is formed. A passage 7 with a partial cut-out is formed on the outer periphery of the stator 4. Reference numeral 8 is a main frame in contact with the inner wall of the closed shell 1. A main bearing 9 is disposed at the center of the main frame. Reference numeral 10 is an auxiliary frame in contact with the inner wall of the closed shell 1. The auxiliary frame has a sliding groove 11 that has an oval hole. The main frame 8 and the auxiliary frame 10 are secured by bolts 13 so as to form a cavity chamber 12.
The scroll compressing member 3 is composed of a first scroll 14 and a second scroll 15. The first scroll 14 is driven by the electric drive member 2. The second scroll 15 rotates in the same direction as the first scroll 14. The first scroll 14 is composed of a cylindrical end plate 16, a spiral wrap 17, and a main drive shaft 18. The spiral wrap 17 is shaped in an involute curve. The main drive shaft 18 protrudes to the center of the other surface of the end plate 16. The first scroll 14 composes a drive side scroll. The second scroll 15 is composed of a cylindrical end plate 19, a ring shape wall 20, a spiral shape wrap 21, and a follower shaft 22. The ring shape wall 20 protrudes to one surface periphery of the end plate and slides on the end plate 16 of the first scroll 14. The spiral shape wrap 21 is surrounded by the ring shape wall and formed on the end plate 19. The spiral shape wrap 21 is shaped in a tooth shape with a compensated involute angle. The follower shaft 22 protrudes to the center of the other surface of the end plate 19. The second scroll 15 composes a follower scroll. The wraps 17 and 21 fit each other in the cavity chamber 12 so that the first and second scrolls 14 and 15 form a plurality of compression spaces 23.
The main frame 8 and the auxiliary frame 10 partition the closed shell 1 as a low pressure chamber 24 and a high pressure chamber 25.
Reference numeral 26 is a drive device. The drive device 26 is composed of a drive pin 27 and a guide groove 28. The drive pin 27 protrudes to the outer periphery of the end plate 16 of the first scroll 14. The guide groove 28 is formed in the radial direction of the ring shaped wall 20 of the second scroll 15. The guide groove is shaped in an U letter shape with an outer cut-out. The circular path of the outer peripheral edge of the guide groove 28 is formed on the outer side of the circular path at the center of the drive pin 27.
Reference numeral 29 is an eccentric bearing member that slidably fits in the sliding groove 11. The eccentric bearing member is composed of an eccentric bush 31 and springs 32 and 33. The eccentric bush 31 has a hole 30 into which the follower shaft 22 of the second scroll 15 is rotatably inserted. The springs 32 and 33 hold the bush from both sides.
The main drive shaft 18 has a discharge hole 34 from which coolant compressed in the compression space 23 is discharged to a high pressure chamber 25. The discharge hole has two discharge openings 35 and 36 that open to the upper portion and the lower portion of the electric drive member 2.
The follower shaft 22 has an intake hole 37 that guides the coolant in the low pressure chamber 24 to the compression space 23. Reference numeral 38 is a connection passage formed on the end plate 19. The passage 38 is connected to the air intake hole 37 so as to deliver the coolant to the compression space 23.
Reference numeral 39 is a small hole formed on the end plate 16 of the first scroll 14. The small hole 39 is connected to the compression space 23 in which the coolant being compressed and the cavity chamber 12. The cavity chamber 12 and the low pressure chamber 24 are sealed by a seal member 40 formed on the sliding surface of the end plate 19 of the auxiliary frame 10 and the second scroll 15. The cavity chamber 12 and the high pressure chamber 25 are sealed by a seal member 41 formed on the sliding surface of the main bearing 9 and the main drive shaft 18.
Reference numeral 42 is an intake pipe. The intake pipe 42 communicates with the low pressure chamber 24. Reference numeral 43 is a discharge pipe that communicates with the high pressure chamber 25.
When the electric drive member 2 of the scroll compressor is rotated, the rotating force is transmitted to the first scroll 14 through the main drive shaft 18. The rotating force of the first scroll 14 is transmitted to the second scroll 15 through the drive device 26 so that the second scroll 15 rotates in the same direction as the first scroll 14. The center position of the eccentric bearing member 29 that fits to the sliding groove 11 deviates from the center of the main drive shaft 18 of the first scroll 14 so that the second scroll 15 rotates about the follower shaft 22.
The first scroll 14 and the second scroll 15 gradually decrease the compression space 23 formed by these scrolls. The coolant that flows from the intake pipe 42 to the low pressure chamber 24 flows from the intake hole 37 of the follower shaft 22 to the compression space 23 through the passage 38 of the end plate 19 so as to compress the coolant. The compressed coolant is discharged from the discharge openings 35 and 36 to the high pressure chamber 25 through the discharge hole 34 formed on the main drive shaft 18 of the first scroll 14. The compressed coolant is discharged to the outside of the closed shell 1 from the discharge pipe 43. The coolant at the intermediate pressure that is being compressed is discharged from the small hole 39 to the cavity chamber 12 so that the resultant compressed coolant works as the back pressure of the first and second scrolls 14 and 15. With a predetermined clearance of the forward edges of the wraps 17 and 21 of the scrolls, the end plates 16 and 19 are slid.
Since the drive device 26 that rotates the second scroll 15 in the same direction as the first scroll 14 forms the circular path at the outer peripheral edge of the guide groove 28 at the outside of the circular path at the center of the drive pin 27, the drive pin 27 can be prevented from dropping from the guide groove 28. The drive pin 27 rotates the second scroll 15 in the same direction as the rotating direction of the first scroll 14 so that the compression space 23 is compressed. Since the center position of the follower shaft 22 is formed in a spiral shape that is an involute shape curve and the wrap 21 of the second scroll 15 is formed in a spiral shape that is a tooth shape curve with a compensated involute angle, when both the first scroll 14 and the second scroll 15 are rotated in the same direction, the compression space 23 is compressed so as to prevent the contact portions of the wraps 7 and 21 from being disengaged and from being abnormally contacted.
Since the seal members 40 and 41 seal the low pressure chamber 24 and the high pressure chamber 25, the low pressure coolant and the high pressure coolant are prevented from entering the cavity chamber 12. The pressure in the cavity chamber 12 is kept at a predetermined intermediate pressure so that the axial sealing force of the first and second scrolls 14 and 15 are maintained in a proper level.
Since the coolant compressed in the compression space 23 is discharged from the upper discharge opening 35 of the electric drive member 2 and the lower discharge opening 36 thereof to the high pressure chamber 25 through the discharge hole 34, the pressure drop of the coolant discharged to the high pressure chamber 25 can be suppressed and the coolant discharged from the discharging opening 36 flows to the discharge pipe 43 through the air gap 6 and the passage 7 of the electric drive member 2, thereby effectively cooling the electric drive member 2 and effectively using the heat given off from the electric drive member 2.
Since the eccentric bearing member 29 is composed of the eccentric bush 31 (which causes the follower shaft 22 of the second scroll 15 to fit to the hole 30 in the sliding groove 11) and the springs 32 and 33 (which hold the eccentric bush 31 from both the sides). Thus, the center of the follower shaft 22 deviates from the center of the main drive shaft 18. In addition, since the springs 32 and 33 hold the eccentric bush 31, when an abnormally high pressure takes place in the compression space 23, the eccentric bush 31 is moved against the elastic force of the springs 32 and 33 in the sliding groove 11 of the oval hole so as to disengage the wrap 21 of the second scroll 15 from the wrap 17 of the first scroll 14. In addition, since the eccentric bearing member 29 does not rotate, the springs 32 and 33, which hold the eccentric bush 31, are not affected by centrifugal force, thereby preventing the spring constants from varying.
By the above-described structure, when an abnormally high pressure takes place, the gap in the radial direction of the wraps of the first scroll and the second scroll can be widened.
As a second related art reference, an embodiment of a scroll compressor as disclosed in Japanese Patent Laid-Open Publication No. 4-12182 will be described. FIG. 9 is a vertical sectional view of this embodiment. For simplicity, the same portions as the first related art reference are denoted by the same reference numerals. Only the different points will be described.
A follower shaft 22 of a second scroll 15 rotates only against an auxiliary frame 10a. The follower shaft 22 does not slide in the radial direction. A seal member 40a is formed between the follower shaft 22 and an auxiliary frame 10a. At discharge openings 35 and 36 formed on a main drive shaft 18, holders 44 and 45, springs 46 and 47, and check valves 50 and 51 are formed. The holders 44 and 45 are mounted on the main drive shaft 18. The check valves 50 and 51 are formed of heavy valves 48 and 49.
In the above-described structure, when the apparatus is operated, centrifugal force is applied to the check valves so as to always open the check valves. With the pressure difference between the discharge hole and the high pressure chamber, the check valves are prevented from being opened and closed. When the apparatus is stopped, it is prevented from being reversely rotated.
As a third related art reference, a scroll type fluid discharging apparatus as disclosed in Japanese Patent Laid-Open Publication No. 50-32512 will be described. FIG. 10 is a horizontal sectional view of a scroll portion of the scroll type fluid discharging apparatus. The outline of the apparatus will be described.
Reference numerals 140 and 141 are two involute spiral wraps of a fixed scroll member. Reference numerals 142 and 143 are two involute spiral wraps of a moving scroll member. As a means for connecting the fixed scroll member and the moving scroll member, a ring 144 is disposed outside both the wraps. Radial protrusions 155 and 156 of the fixed scroll member are slidably formed at a lower groove of the ring 144. Radial protrusions 157 and 158 secured to the wraps 140 and 141 slidably fit to an upper groove of the ring 144. While the apparatus is being driven, the moving wraps 142 and 143 are pressed to the fixing wraps 140 and 141 by centrifugal force so as to hold a radial seal in the compression space.
Each of the rotating type scroll compressors described as the first and second related art references has a shaft portion on the rear surface of the mirror surface on which the scroll wrap is formed. The shaft portion is supported in an over-hang structure at a position apart from the wrap to which the load of the compressed fluid is applied. Thus, the moment at which the scroll member becomes unstable may take place.
In addition, the radial seal technique in the compression space of the scrolls uses centrifugal force in the case of the sliding type as described in the third related art reference. However, in the rotating type, since both the wraps are rotated, the centrifugal force cannot be used. Thus, to improve the efficiency, the gap in the radial direction should be minimized. In the conventional fixed eccentric system, the assembling accuracy was very important.